Enforcement of fishery agreements , where they do exist , for commercial fisheries has been confounded by the wide and patchy distribution of such fishery resources , and the obsolete belief that marine resources are inexhaustible 由于該等漁業(yè)資源的分布范圍廣泛而不平均,加上人們?nèi)杂泻Q筚Y源取之不竭的過(guò)時(shí)觀念,故此執(zhí)行商業(yè)性捕魚(yú)的管制協(xié)議往往困難重重。
Moreover the cases of evaluating the fish resources in the upper yangtze river by using basic data were much less . this research evaluates the fishery status in the upper yangtze river by using commercial fisheries data of hejiang section from 1999 to 2002 . the age , growth and mortality of rhinogobio ventralis which is endemic to the upper yangtze river have been studied also . moreover we have estimated the biomas s of rhinogobio ventralis 本文是在實(shí)地調(diào)查的基礎(chǔ)上,結(jié)合水生生物流動(dòng)監(jiān)測(cè)站合江站1999 - 2002年的監(jiān)測(cè)結(jié)果,對(duì)長(zhǎng)江上游合江段的漁業(yè)捕撈現(xiàn)狀進(jìn)行了評(píng)估,研究了重要的經(jīng)濟(jì)特有魚(yú)類長(zhǎng)鰭吻?的年齡、生長(zhǎng)和死亡,并對(duì)其資源量進(jìn)行了估算。